1	Style unbranched or rarely with branches shorter than 1.5 mm; tepals never scarlet.		(2)
+	Style obviously branched, branches longer than 1.5 mm; tepals sometimes scarlet.		(5)
2 (1)	Tepals shorter than 2 cm or, if longer, then yellow to orange.		(3)
+	Tepals 2 cm or longer, white to pink or pinkish purple.		(4)
3 (2)	Leaves whorled proximally; tepals pinkish to purplish; s California.		5 Fritillaria brandegeei
+	Leaves subopposite to scattered; tepals yellow to orange; n California to British Columbia, e to Wyoming.		16 Fritillaria pudica
4 (2)	Tepals pinkish purple, obovate, apex rounded to acute, not recurved; flowers not noticeably fragrant; n California.		15 Fritillaria pluriflora
+	Tepals white to pink, oblanceolate, apex acute to apiculate, usually recurved; flowers fragrant; s California.		19 Fritillaria striata
5 (1)	Tepals red or scarlet, sometimes to maroon or purplish, clearly checkered or mottled, apex usually recurved, sometimes only spreading.		(6)
+	Tepals sometimes mottled or rarely scarlet, but never both, apex not recurved, only rarely slightly recurved.		(7)
6 (5)	Perianth slender; tepal apex usually strongly recurved, nectaries ¼ tepal length or less; style branches ± erect; n California, s Oregon, w Nevada.		18 Fritillaria recurva
+	Perianth broadly campanulate; tepal apex spreading, not recurved, nectaries 1/2 tepal length; style branches widely spreading; s Oregon.		9 Fritillaria gentneri
7 (5)	Leaves more than 10 or in whorls of 2–6(–9) per node proximally, blade linear to narrowly to broadly lanceolate to rarely ovate.		(8)
+	Leaves 10 or fewer and/or alternate, blade sometimes sickle-shaped.		(15)
8 (7)	Flowers ± erect, occasionally nodding; distal leaves usually ca. 1/3–1/2 length of proximalmost leaf; leaves often longer than inflorescence; only in California.		14 Fritillaria pinetorum
+	Flowers nodding or occasionally spreading; distal leaves usually ± equaling proximalmost leaf; leaves usually shorter than inflorescence; more widespread.		(9)
9 (8)	Tepals purplish brown, mottled yellow or white; leaves 2–3 per node proximally; 1000–3200 m, especially inland mountains.		3 Fritillaria atropurpurea
+	Tepals greenish white, greenish yellow to red, purplish, or nearly black, mottled or not; leaves usually more than 3 per node proximally; 0–1800 m, especially in coastal mountains.		(10)
10 (9)	Tepals dull greenish yellow, dark-dotted, nectaries widely elliptic to ± diamond-shaped, paler than tepals; s California.		13 Fritillaria ojaiensis
+	Tepals greenish white, pale green or greenish yellow to red, purplish, or almost black, sometimes mottled, nectaries lanceolate or linear, variously colored; s California to Alaska.		(11)
11 (10)	Tepals pale green to almost black, not mottled, nectaries ca. 1/2 tepal length, green; small bulb scales 0–4; s California.		20 Fritillaria viridea
+	Tepals greenish white, pale greenish yellow to red, greenish brown to purplish, or pale yellowish green, sometimes mottled, nectaries variously colored, less than 1/2 tepal length (nearly equaling tepal length in F. camschatcensis, but very narrow and obscure; to 2/3 tepal length in F. affinis); small bulb scales usually 10 or more, rarely fewer; c California to Alaska.		(12)
12 (11)	Tepals usually 2 cm or longer, often clearly purple- or yellow-mottled.		(13)
+	Tepals usually shorter than 2 cm, mottling absent or faint.		(14)
13 (12)	Tepals clearly purple- or yellow-mottled and small bulb scales 20 or fewer, or tepals not mottled and bulb scales 50 or more; nectaries lanceolate, to 2/3 tepal length; flower odor not unpleasant.		1 Fritillaria affinis
+	Tepals dark greenish brown to brownish purple; small bulb scales 30 or more; nectaries obscure, linear, ± equaling tepal length; flower odor unpleasant.		6 Fritillaria camschatcensis
14 (12)	Style branches barely recurved; tepals greenish yellow to red, apex usually flared to slightly recurved, nectaries green, gold, or yellow.		7 Fritillaria eastwoodiae
+	Style branches strongly recurved; tepals purplish to greenish white, apex not flared or recurved, nectaries greenish white, dotted purple.		12 Fritillaria micrantha
15 (7)	Tepals clearly mottled; small bulb scales usually 10 or more, rarely fewer.		(16)
+	Tepals not clearly mottled; small bulb scales fewer than 10.		(19)
16 (15)	Leaf blade sickle-shaped; flowers erect; San Francisco Bay region and s coastal mountains of California.		8 Fritillaria falcata
+	Leaf blade usually not sickle-shaped; flowers usually horizontal or nodding, sometimes ± erect; not in San Francisco Bay region and s coastal mountains of California.		(17)
17 (16)	Leaves 2–10, blade ovate, a few sometimes sickle-shaped; tepals white, spotted purple; small bulb scales 0–3.		17 Fritillaria purdyi
+	Leaves usually 4 or more, blade linear to lanceolate; tepals purplish brown, mottled greenish yellow, yellow, or white; small bulb scales 45–50.		(18)
18 (17)	Flowers nodding; distal leaves slightly less than or equaling proximalmost leaf, leaves usually shorter than inflorescence.		3 Fritillaria atropurpurea
+	Flowers ± erect; distal leaves usually 1/3–1/2 length of proximalmost leaf; leaves longer than inflorescence.		14 Fritillaria pinetorum
19 (15)	Leaves 2–4, blade sickle-shaped.		10 Fritillaria glauca
+	Leaves usually more than 4, blade not sickle-shaped.		(20)
20 (19)	Nectaries obscure, forming narrow band 1/2–2/3 tepal length; tepals white, striped green; flowers odorless or faintly fragrant; coastal.		11 Fritillaria liliacea
+	Nectaries prominent, forming narrow band 2/3 to equaling tepal length; tepals brown, purplish brown, or greenish purple at least adaxially; flowers odorless or with unpleasant odor; inland.		(21)
21 (20)	Tepals greenish white or yellow abaxially, purplish brown adaxially; flower odor definitely unpleasant; usually in clay depressions.		2 Fritillaria agrestis
+	Tepals dark brown to greenish purple or yellowish green; flowers odorless or sometimes with unpleasant odor; usually on hillsides and mesas.		4 Fritillaria biflora